Disclosure of Invention
Aiming at the defects of the prior art, the coating agent for the drilling fluid is prepared by the method provided by the invention.
The preparation method of the coating agent for the drilling fluid comprises the following operation steps:
a. mixing 41-55 parts of water, 12-23 parts of allyl amine, 5-13 parts of sodium chloroacetate and 0.5-1.5 parts of sodium carbonate, keeping the temperature at 75-85 ℃ for 6-8 hours, cooling to room temperature, adding 3-5 parts of toluene-2, 4-diisocyanate, and stirring for 30min to obtain solution A;
b. mixing 23-35 parts of mineral oil, 2-5 parts of emulsifier OP-4 and 1-3 parts of emulsifier OP-7, and stirring for 30 minutes to obtain solution B;
c. mixing the solution A prepared in the step a with the solution B prepared in the step B, stirring at the rotating speed of 3000r/min for 2 hours, adding 0.05-0.2 part of ammonium persulfate and 0.05-0.2 part of tetramethylethylenediamine, and stirring for 12-20 hours to obtain a coating agent for drilling fluid;
the above are all parts by mass.
As a further improvement of the invention, the mineral oil is a carbon chain C14~C22Of (a) an alkane.
The coating agent for the drilling fluid prepared by the method has a strong coating inhibition effect, can increase the rolling recovery rate of rock debris, and has an effect superior to that of a commercially available FA367 comparative example. The polymer coating agent overcomes the defects that the existing polymer coating agent has poor coating capability due to the fact that a network cannot be formed in complex strata such as water sensitivity and the like, and the prepared polymer coating agent has the characteristics of strong dispersion inhibition, strong temperature and salt resistance and high dissolution speed.
The specific implementation mode is as follows:
example 1
A preparation method of a coating agent for drilling fluid comprises the following operation steps:
a. mixing 41-55 parts of water, 12-23 parts of allyl amine, 5-13 parts of sodium chloroacetate and 0.5-1.5 parts of sodium carbonate, keeping the temperature at 75-85 ℃ for 6-8 hours, cooling to room temperature, adding 3-5 parts of toluene-2, 4-diisocyanate, and stirring for 30min to obtain solution A;
b. mixing 23-35 parts of mineral oil, 2-5 parts of emulsifier OP-4 and 1-3 parts of emulsifier OP-7, and stirring for 30 minutes to obtain solution B;
c. mixing the solution A prepared in the step a with the solution B prepared in the step B, stirring at the rotating speed of 3000r/min for 2 hours, adding 0.05-0.2 part of ammonium persulfate and 0.05-0.2 part of tetramethylethylenediamine, and stirring for 12-20 hours to obtain a coating agent for drilling fluid;
the above are all parts by mass.
Wherein the mineral oil is carbon chain C14Of (a) an alkane.
Example 2
A preparation method of a coating agent for drilling fluid comprises the following operation steps:
a. mixing 41-55 parts of water, 12-23 parts of allyl amine, 5-13 parts of sodium chloroacetate and 0.5-1.5 parts of sodium carbonate, keeping the temperature at 75-85 ℃ for 6-8 hours, cooling to room temperature, adding 3-5 parts of toluene-2, 4-diisocyanate, and stirring for 30min to obtain solution A;
b. mixing 23-35 parts of mineral oil, 2-5 parts of emulsifier OP-4 and 1-3 parts of emulsifier OP-7, and stirring for 30 minutes to obtain solution B;
c. mixing the solution A prepared in the step a with the solution B prepared in the step B, stirring at the rotating speed of 3000r/min for 2 hours, adding 0.05-0.2 part of ammonium persulfate and 0.05-0.2 part of tetramethylethylenediamine, and stirring for 12-20 hours to obtain a coating agent for drilling fluid;
the above are all parts by mass.
Wherein the mineral oil is carbon chain C18Of (a) an alkane.
Example 3
A preparation method of a coating agent for drilling fluid comprises the following operation steps:
a. mixing 41-55 parts of water, 12-23 parts of allyl amine, 5-13 parts of sodium chloroacetate and 0.5-1.5 parts of sodium carbonate, keeping the temperature at 75-85 ℃ for 6-8 hours, cooling to room temperature, adding 3-5 parts of toluene-2, 4-diisocyanate, and stirring for 30min to obtain solution A;
b. mixing 23-35 parts of mineral oil, 2-5 parts of emulsifier OP-4 and 1-3 parts of emulsifier OP-7, and stirring for 30 minutes to obtain solution B;
c. mixing the solution A prepared in the step a with the solution B prepared in the step B, stirring at the rotating speed of 3000r/min for 2 hours, adding 0.05-0.2 part of ammonium persulfate and 0.05-0.2 part of tetramethylethylenediamine, and stirring for 12-20 hours to obtain a coating agent for drilling fluid;
the above are all parts by mass.
Wherein the mineral oil is carbon chain C22Of (a) an alkane.
When in use, the drilling fluid can be directly added into the drilling fluid for use, the clay expansion is inhibited, the drilling cuttings are coated, and the addition amounts are as follows: the mass percentage is 0.1-0.5%.
The following is a coating agent prepared by the preparation method, and the superior performance of the coating agent is measured.
1. Swelling test
The measuring method is direct measurement by an instrument. The swelling experiment shows the hydration property of the product, the larger the swelling amount is, the stronger the hydration property is, the poorer the swelling inhibition capacity of the bentonite is, and the larger the influence on the stratum is, which is an adverse influence factor on the stratum. According to the experiment, the artificial rock core is pressed by bentonite according to the standard requirement of the shale expansion experiment, the shale expansion experiment is carried out on a shale expansion instrument according to the shale expansion test standard, the inhibition and anti-expansion capacity of the coating agent on the shale is evaluated, the expansion amount of 8 hours is measured in a 10% sodium chloride brine system, and the experiment result is shown in table 1.
TABLE 1 results of swelling amount experiment
Example 1
|
Expansion amount mm
|
Example 2
|
Expansion amount mm
|
Example 3
|
Expansion amount mm
|
FA367
|
Expansion amount mm
|
0.1%
|
6.6
|
0.1%
|
6.3
|
0.1%
|
6.5
|
0.1%
|
9.1
|
0.2%
|
6.3
|
0.2%
|
6.1
|
0.2%
|
6.1
|
0.2%
|
8.9
|
0.3%
|
5.7
|
0.3%
|
5.4
|
0.3%
|
5.5
|
0.3%
|
8.3
|
0.4%
|
5.5
|
0.4%
|
5.1
|
0.4%
|
5.3
|
0.4%
|
8.1
|
0.5%
|
4.9
|
0.5%
|
4.6
|
0.5%
|
4.8
|
0.5%
|
7.8 |
As can be seen from Table 1, in examples 1-3, the swelling amount decreased with the percentage increase, because the product of this example has the function of inhibiting the clay swelling. The swelling amount of FA367 used in 10% sodium chloride brine is still higher than that of the lowest percent in examples 1-3 at the highest percent, so that the coating agent produced by the preparation method of the invention has extremely strong coating inhibition effect, because the swelling inhibition effect of the product of the example is improved by introducing allyl amine monomer.
2. Heat roll-back yield determination
The temperature resistance is reflected by the high and low of the hot rolling yield measurement. Adding 350mL of test solution (blank is tap water, and the percentage is the mass percentage of the coating agent added) into an aging tank, weighing 50g of shale debris of 5-10 meshes, and respectively rolling and dispersing in a roller furnace at 150 ℃/200 ℃ for 16 h; then, screening and washing the recovered rock sample in water by using a 40-mesh sieve, putting the rock sample left by the sieve into a watch glass, and drying the rock sample in a 105 ℃ drying oven to constant weight; the weight was measured and the heat rollback yield was calculated from the following formula (see table 2 for results):
S=M/50×100%
in the formula: s-recovery after 40 mesh screen,%; m-the balance of the sieve of 40 meshes, g.
TABLE 2 results of heat rollback yield determination
As can be seen from Table 2, the heat rollback yield decreased with increasing temperature at the addition of 0.5%, but it was not significant because the examples prepared by the preparation method of the present invention were thermally stable. Meanwhile, under the condition of the same addition amount, the hot rolling yield of the coating agent prepared by the preparation method is obviously higher than that of the coating agent of FA367 on the market, so that the product has stronger temperature resistance and wider application range in the drilling process.
3. Solubility test
200mL of tap water was added to 1g of the sample of example, and the mixture was stirred and dispersed at a rotation speed of 150r/min, and the dissolution and dispersion time was measured.
TABLE 3 dissolution time for each example
Comparative example
|
Dissolution time
|
FA367
|
7716s
|
Example 1
|
236s
|
Example 2
|
261s
|
Example 3
|
277s |
As can be seen from Table 3, the dissolution time of each example is less than 5min (300 s), and the dissolution speed in water is very fast and is far faster than that of the similar coating agent comparative example. This is because in the examples prepared by the preparation method of the present invention, the hydrophilic group-CH 2 COO-is introduced, and the water-soluble dispersion speed is high.
Meanwhile, by combining the tables 1, 2 and 3, the product can effectively play a role of coating, can increase the rolling recovery rate of rock debris, has short dissolution time and is more suitable for market popularization under the condition of 0.5 percent addition.